Automatic telephone system



vJ. WICKS AUTOMATIC TELEPHONE SYSTEM I 7 Filed Oct. 23, 1920 3 Sheets-Sheet l Tnuanlfr Jul-m hliaxa 1,520,268 J. WICKS AUTOMATIC TELEPHONE SYSTEM Filed Oct. 23, 1920 5 Sheets-Sheet 2 N Q Q J. WICKS AUTOMATIC TELEPHONE SYSTEM Filed Oct. 23, 1920 3 Sheets-Sheet 8 Irwin 01-" 'system, and they will not operate in the particula'r type of selective ringing1system herein Patents Dec. 23, I924.

JOHN WICKS, OF CHICAGO, ILLINOIS, ASSIGNOR '1'0 AUTOMA'IIG ELECTRIC CO OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS I i AUTOMATIC TEI EPHONE sys'rmr.

. Application filed ember as, 1920. Serial No. 418,944.

To all whom it may comer-n: Be it known that I, JOHN Wrens, a citizen- 'of the United States of America, and 'a resident of Chicago, Cook County, and State of Illinois, have invented certain new and-'- useful Improvements in .Automatioflele, phone Systems, of which the following is a specification. I 1'1. This invention relates in general to automatic telephone systems, but more especially to automatic party line systems of the type commonly knownu'as semi-selective, in which each party linehas two one bell stations and two. two belllstations 0on nected from opposite sides of the-,lineto ground; and the object of the invention, stated broadly,' isf to provide suitable ring back switches and associated apparatus through the medium of which any subscriber 20 on a party linejicansignal any. other sublscriber on the 'sam'line. Ri backfswitches have been designed'before ti'isj to'handle' the reverting callsin automatic party line systems, but the former' -ringback equipments are intended to operate, in other types of selective signalling'lsystems', as-for example, the well known armonic contemplated. New circuits. ave been devised, therefore, 'suitable'for use v infa party line signalling system of the semi-selective type, and thus a new ring back equipment is produced which is adapted for use in a situa tion where the known ring back equipments would be of no utility. g The invention, thuslbriefly set forth in its essential features, will be described fully; Y hereinafter, reference being had to the accompanying drawings, comprising Figs. 1, 2, and 3, wherein is shown by means of-the usual circuit diagrams enough of the apparatus in a telephone system-to enable the invention to be understood. I Referrin now to Fig. 1, there is shown at the upper left hand corner of the sheet a four party line comprising conductors 6 and 7, and automatic telephone substations 1 to 4, inclusive. Substations Land 3 are one hell stations, while substations2 and 4 are two bell stations. The ringers at stations -1 and 2 are connected from line conductor? as in the drawing, While theringers at the two remaining stations are connected from lineconductor 6 to groun ;A;t the'exchange the party line terminates finl'an individual line or trunk selecting switch which iSQindicated by reference character Thelineswitch C is of the well fiiknown rotary in which the wipers have no 'no'rmal position and move in aforward direction only, andin common with other similar line switches has access to a grou I of trunk switc es. 5

lines leading to firstselector which "1s a-switch of the usual Strowger vertical and rotary type and is operated according to the well knowntwowire system of control, as are all the otherswitches in the system, The selector E-has 10 levels of bankcontacts jand'one of the levels, as, for

example, the first, may-be, reserved for the reverting call, apparatus, or ringback switches. The other; levels serve to give access to the'diflerentjgroups of second selectors.

cuits of the switch are controlled by the One of the reverting call trunk lines which is accessible. to'theselector. E' and similar selectors is shown as extending to the ringback switch F, Fig. 2., This switch comprises wipers 88 and 89, the stepping magnet 84, and the release magnet 160. The cirrelays shown at the left, whose operation and function will be explained.

Gooperatingwith theringback switch F and-a plurality of similar ringback. switches is a common mechanism shown in Fig. 3.

This mechanism comprises a. solenoid in-.

terrupter M and a group of relays associated therewith, whose function is to project ringing current according to the proper codes over either or both conductors of a calling 4 line, the precise ringing operation performed being determined by the selective operation of the ring back switch in use. In order to,

enable any subscriber to initiate the proper ringing operation required to signal any other subscriber on his line, code call numbers are assigned, and each subscriber is furnished with a list of the numbers pertaining to his particular station. The table below is a complete list of all numbers required for a four party line.

Station No. 1 calling Station No. 2 dial 11 66 66 l 66 66 66 3 66 66 66 l 66 66 66 4 66 66 66. 2 66 66 66 1 66 66 66 2 66 66 v 66 3 66 66 66 2 66 66 66 4 66 66 66 3 66 66 66 4 66 66 66 3 9, 66 66 1 66 66 66 3 66 66 66 2 I 66 it 66 4 66 66 66 3 66 66 66 4 66 66 66 l 66 66 66 4 66 66 66 2 66 The subscribers at stations 1 and 3 are instructed to respond to one long ring and the subscribers at stations 2 and 4 are 1nstructed to respond to two short rings.

I will now describe the difi'erent signall ng operations which may be performed, it be ng assumed first that the subscriber at station 1 desires to call the subscriber at station 2.

When the receiver is removed from the switch-hook preparatory to making a call, a circuit is closed for the line relay 5 over the line conductors 6 and 7 in the well known manner. Line relay 5' energizes andcompletes a circuit for switching relay 8 at armature 9, and at armature 10 connects the private wiper 12 to the above circuit at a point midway between the switching relay and the motor magnet. that the trunk selecting operation of the lineswitch C is well known, we will assume that the trunk line upon which the wipers 11 to 13, inclusive, are resting is idle. Under these circumstances relay 8 will energizes immediately after line relay 5 has operated, with the result that the line conductors 'i' and 6 are disconnected from the winding of line relay 5 and ground, respectively, and are extended by way of armatures 14 and 15 and their working contacts, wipers 11 and 13, bank contacts 16 and 17, and armatures' 18 and 19 and their resting contacts to the up.- per and lower windings of line relay of selector 1*].

As soon as the line is extended to selector E, as above described, the line relay 25 will be energized and will operate to close the circuit of slow acting release relay 26.

Upon energizing, the latter relay prepares the vertical magnet circuit at amature 29 and its front contact, and atarmature 27 and its front contact places ground G on conductor 28, thereby establishing a holding circuit which extends by way of bank contact 20, wiper 12, armature 21- and its front contact, winding of switching relay 8 and the stepping magnet to battery. It will be understood that the above tracedholding circuit is completed before the slow acting line relay 5 has deenergized. Besides maintaining the switching relay energized, this Because of the fact maaaee this case is the digit 1. One interruption is thereby reduced in the circuit of line relay 25, whic on retracting its armature com.- pletes a circuit for vertical magnet 30 in series with slow acting relay 29. By the operation of the vertical magnet the shaft carrying the wipers to 37, inclusive, is

raised opposite the first level of bank con-' tacts, in which trunk lines leading to the ringback switches terminate. The slow acting relay 29 is energized in series with the vertical magnet and upon the first vertical etc of the shaft, ofi' normal springs 41 and 42 aving closed, a circuit is completed from ground on conductor 28 by Way of armature 43 and its front contact, ofl' normal springs 42, and the winding of relay 44 to battery. This latter relay, on attracting its armature 46, completes a locking circuit for itself, and also prepares the circuitof rotary magnet 50. At end of the vertical movement of the switch, relay 29 deenergizes and closes the circuit of rotary magnet which operates to advance the wipers 35 to 37 inclusive, into engagement with the first set of bank contacts in the first level. The rotary magnet 50 also breaks the locking circuit of relay lOO 44 which accordingly deenergizes and breaks the circuit of the rotary magnet, which also deenergizes. The further operation of the switch depends on whether or not the first trunk line is busy or idle. if busy, the test contact engaged by wiper 36 will be grounded, and a circuit is completed from the grounded test contact by way of wiper 36, conductor 49, springs 48, springs 42, and relay 44 to battery. Relay 44 therefore again operates to again close the rotary magnet circuit. The alternate operation of relay 44 and rotary magnet 50 will continue until an idle trunk is found, which we will assume is the trunk line terminating in bank contacts 38, 39, and 40. No ground will be present on the bank contact 39 when engaged by wiper 36 and relay 44 therefore will not again pull up, but relay 51, which is no longer shorted, will energize in series with relay 44 in the usual manner. Upon energizing relay 51 disconnects the incoming line conductors from the windings of line relay 25 and extends them by way of armatures 18 and 19 and the front contacts, wipers 35 and 37, bank contacts 38 and 40, trunk conductors 54 and 56, armatures 60 and 61 and their resting contacts, and the amazes of line relay 7 5.

u per and lower windin oi gs to battery and conductor extending back to switching rela 51 of selector F, and switclnng relay 8 o lineswitch C, to hold these relays in their operated position.

The subscriber at station 1 may now operate his calling device for the last di it of the number, which in this case will a so be the digit 1, thereby producing one interruption in the circuit of line relay 75. On retracting its armature, relay 75 completes a circuit from ground G by way of armature 79 and its back contact, armature 77 and its front contact, conductor 80, armature 81 and its back contact, conductor 83, and the rotary magnet 84 to battery, there being a branch circuit in multiple with the above which extends throughthe slow acting relay. 85 to battery. When its circuit is closed the rotary magnet 84foperates to ro-' tate the shaft carrying wipers 88 and 89 on to the first set of bank contacts; 90 and 91 in an obvious manner. 0n the first rotary step of the switch ofi normal springs 92 and 99 close. Relay'85 is energized .in arallel with the rotary magnet and when the relay falls back, an instant after theimpulse to the rotary magnet has been sent, a circuit is completed from ground on conductor 94 by way of springs 92, back contact and armature 95, and the winding of relay 96 to battery. Relay 96, upon energizing, locks itself at armature 97, and at armature 81 opens the rotary magnet circuit.

No further operation of the ringback switch will take place until the calling subscriber hangs up his receiver, thus opening the circuit of line relay 75. Relay 75, on retracting itsarmature, opens the circuit of slow acting relay 76 and also, before relay 76 deenergizes, sends'an impulse of current to slow acting relay 85, which energizes. When relay 76 falls back it will break the circuit of relay 85 but before the latter relay has time. to deenergize a circuit is closed which extends from ground Gr by way of armature 79 and its back contact, armature 77 and its back contact, armature 98-and its front contact, and through the winding of relay 100 to battery. On attracting its armatures this relay locks itself overa circuit extending from ground G by way of armature 101 and its front contact, conductor 94, grmature 101 and its back contact, conductor 103, and armature 104 and its front contact,

and through relay 100 to battery. This ground also extends over conductor 55 to switching relays 51 and 8 of selector E and places ground line switch 0, respectively, to maintain theseswitchesin' their operated positions. After slow acting release relay 76 had deenergized and before relay 100 energized these preced' ing switches were held up by ground from the armature of slow acting relay 85, which deenergizes shortly after the energization of relay 100. Relay 100 also closes a circuit extending. from ground G", through armature 109 and its front contact, conductor 110, and the winding of relay 111 to battery. Relay 111 attracts its armature and places battery, at armature 112 and itsfront contact, on conductor 113, which extends by way of wiper 114, and the winding of solenoid 115 of-the solenoid interrupter M to ground.

' This solenoid interrupter is the rin ing interrupter, whose operation will be briefly described before continuing with the circuit explanation. When the winding 115 cher gizes the solenoid pulls up its plunger 117 carrying wiper 123 at once, and upon the wiper reaching the top-contact 125 the pm 118 will move the arm, 120 into its alternate position, thus openinglthe contact at wiper 114. The wiper willremain in this osition until'pin 121 moves the arm 120 into its original position, this occurrin when the shaft is again normal. The plunger arm 117 is so constructed that While it will be known ,manner, as Jby'meansof a dashpot.

although ground is placed successively on the ringing 'ys' s p ace so fas thatf 1 none of the relays are operated.

.Returning againto the ringing operation,

,upon the wiper 1'23 engaging contact 125 in its downward motion a circuit is completed from ground G through contact 124, wiper 12 3, contact 125, conductor 126, winding of relay 127, and conductor 128 to battery. Re-

lay 127 will energize and at armature 131 and its front contact,"place ground G on conductor 132 extending through armature 133 and its front, contact, and the winding of relay 134 to battery. This latter relay, on attracting its armature, locks itself to ground on conductor 55 and completes the ringing circuit for the called subscribers telephone, extending from the ungrounded pole of generator G, conductor 135, front I contact and armature 129, conductor 130,,

bank contact 90,-wiper 88, ring'cut off relay 136, conductor 137 front contact and armature 60, conductor 54, bank contact 38, wiper 35, front contact and armature 18, bank contact 16, wiper 11, front contact and-armature 14 to line conductor 7., thence through the ringers of substations 1 and 2, on the party line, to ground. The ringers at both substations respond for a short interval but the circuit is soon broken because the inter- 95,- pulledup rapidly bywinding 115 its "return i Y to normal will'take an'appreciable time, the slowdescent beingaocomplished in anywell.

armature 146 places generator on conductor 152 extending to bank contact 153 but since the wipers 88 and 89 of the ring back switch are not in engagement with this set of bank contacts the operation of relay139 has no effect at this time. Now upon the contactor 123 reaching contact 154 ground is placed on conductor 155 extending through 140 to battery. On energizing, relay 140 at armature 142 again places generator on conductor 130 and thus reestablishes the ringing circuit extending, back to substations 1 and 2. This will operate the ringers there for another short period. Two short rings is the call signal of two bell station 2 and the subscriber thereat will know that he is being called." The bell at substation l'will also be actuated andthe calling subscriber thereatis thus notified that the ap ara-tus is working properly and that the su scriber at station 2 is being signalled.

As the plunger arm of the solenoid interrupter descends ground will be placed successively on contacts 156 and 157 and relays 158 and 160, and 189 and 160, will be operated, but their operation will have no effeet at this time. Upon the plunger arm 117 reaching its normal position, pin 121 moves arm 120 into its normal position, thereby again closing the circuit for the solenoid winding 115. This same ringing operati n as heretofore described is then repeated and will continue until the subscriber at substation number 2 removeshis receiver, thereby permitting direct current to flow over the previously traced ringing circuit to the subscribers telephone (not shown, but exactly like the telephone at station 1), then through switch-hook springs receiver and transmitter to line conductor 6, thence over .a circuit similar to the one above traced to wiper 89 of the ringback switch, and thence by way'of bank contact 91 to ground. Had subscriber at station 2'removed his receiver during a-silent period the circuit for relay 136 would be completed from battery B on conductor 190 instead of from batteryB atthe ringing generator. Relay 136 will energize, opening the locking circuit of relay 100 at armature 102. Relay 100, on deenergizing completes the circuit for the release magnet 160 this circuit extending from ground G armature 7 9 and its back contact, arma ture 77 and its back contact, armature 98 and its back contact, armature 188 and its back contact, oii' normal springs 99, conductor 159, and the winding of release magnet 160 to battery. Magnet 160 will operate to restore the switch to .its normal condition. Upon retractingits armature 101, relay 100 removes ground from conductor extendin back to switching relays 51 and 8.01. seiiactor Efand lineswitch C, and also removes the ground from conductor 110 at armature- 109 which has hitherto maintained ringin interrupter M in continuous operatron. Switches E, and C are thus released and the operation of the interrupter M is stopped. I i

When the selector E and lineswitch (J are restored, relay 8, on deenergizing, again completes the circuit of line relay 5 of lineswitch C,v as the subscriber at station 2 has his receiver off the switchhook, and a circuit is again closed for relay 8, which oper ates as before to extend the line conductors to the upper and lower windings of line relay 25 ofselector E.

As subscriber at station 1 no longer hears the ringing of his hell he will'know that the subscriber at station 2 has responded, wheretion to cease and the release of the switches would take place when the receiver was re placed.

I will now briefly describe the operation of the apparatus when the subscriber at station 1 calls the subscriber at-station 4, a party whose ringer is connected from the opposite side of the lineto ground and who is instructed to respond to 2 short rings. To make this call it will be seen from the table shown hereinbefore, that the number the subscriber at station 1 will dial will be 13. The operation of the lineswitch G, first selector E and ring back switch F is'the same as hereinbefore described, except that instead of one impulse being sent to rotary magnet- 8 1 of the ringback switch F, three impulses will be sent and wipers 88 and 89 will be rotated into engagement with the third set of bank contacts. The solenoid interrupter M and relays will operate as before described but a difierent group of relays will supply the ringing current to the party line, because wipers 88 and 89 are now resting on the third set of bank contacts. lhese operations will doubtless be clear but may be briefly described nevertheless. When contactor 123 of the solenoid interrupterv engages contact 125 a circuit is completed for relay 127 in an obvious manner and this relay closes the circuit of the picl: up relay 134 at armature 131. At armature 161, gen erator is placed on conductor 162 and a circuit is closed by way of bank contact 163, wiper 89, the lower heavy line conductor and through the ringers of substations 3and 4 to ground. Now as soon as wiper 123 disengages contact 125, relay 127 deenergizes opening the above traced ringing circuit. When contactor 123 engages contact 154 a circuit will be completed for relay 140, which on energizing again connects generator to conductor 162 and thence to the ringers of substations. 3' and 4 whose bells will be again actuated for a short period. Thus. two short rings will be produced at two'bell substation 4. Upon wiper 123 engaging contact 156 a circuit for relay 189 is completed. This relay on attracting its armature 188 closes the circuit of relay 160,. This latter relay on attracting its armature 189' places generator on conductor 164, and closes a ringing circuit extending by way of bank contact 165, and wiper 88 to the upper side of the line, whence it goes through the ringers of substations 1 and 2 to ground. As soon as wiper 123 of solenoid M reaches contact 157 a circuit is completed for relay 158, which on energizing p aces ground on conductor 166 extending to relay 160 to maintain this relay energized. The circuit through relay 158 is closed before the circuit of relay 189 is broken and thus the ringer at station 1 will be actuated for one long ring to notify the calling subscriber that his call is proceeding satisfactorily. This ringing of the called and calling subscribers will continue alternatelyuntil the subscriber at station 4 answers whereupon the operation will proceed as herein before described.

Should the wipers 89 and 88 of the ringback switch F be rotated into engagement with contacts 170 and 171 by the subscriber at station 1 or the subscriber at station 3, relays 140 and 139' of the relay group will be actuated successively and as each coinplates the circuit of-relay 183, one long ring will be sent from generator G by way of armature 180 and its front. contact, conductor 181, bank contact 171, wiper 88, to the substations 1 and 2. The operation of relays 189 and 158 will also be efiective at this time, and as each completes the circuit of relay 160, one long ring will also be sent to substations number 3 and 4 from n-.

erator G by way of armature 189' an its front contact. Thus stations 1 and 3 would be signalled.

the-operation of relays 139 and 140 would be efi'ective as before to send one long g to substations numbers 1 and 2. This woul be the case if the subscriber at station 2 wer calling the subscriber at station- 1.

If wipers 88 and 89 were on contacts 174 and 175, relays 127 and 140 would operate to send 2 short rings to stations 1 and 2 and relays 139 and 140 would operate to send one long ring to stations 3 and 4, thereby signalling the subscribers at stations 2and 3.

If wipers 88 and 89 had been rotated on to bank contacts 151 and 153, relays 127 and 140 would then operate to give two short rings to stations 1. and 2, and relays 139 and 158 would operate to give two short rings to stations 3 and4. This signals the subscribers at stations 2 and 4.

Had wipers 88 and 89 been rotated into engagement with bank contacts 176 and 177,

the operation of relays 127' and 140 would have been efi'ective to send two short rings to stations 3 and 4 on the party line. This would be the. case if the subscriber at station 3 were calling the subscriber at station 4.

If the wipers had been rotated on to bank contacts 178 and 179, as where the subscriber at station 4 calls the subscriber at station 3, relays 140 and 139 in operating would be efiective to energize relay 183 to send a long ring to stations 3 and 4.

' Having fully described and ascertained the features of this invention, what I consider to be new and desire to have protected by Letters Patent will be pointed out in the appended claims.

What I claim as my invention is:

1. In a telephone system, the combination, i

with a party line provided with substation r ngers connected from the same side of the lmeto ground, of a grounded ringing generater, automatic ringing equipment, auto-' 1 matlc means controlled over said line for extending a connection to said equipment, and automatic means including said equipment for variably connecting the ungrounded pole of said generator to the ringer conductor of said line to selectively of the line to ground, of, a grounded ringing generator, automatic means controlled over said line for extending a connection to said generator, automatic means for connecting either conductor of said line to the ungrounded ole of said generator over a circuit including said extended connection, and code ringing means cooperating with said generator to selectively signal, all the v parties on said party line.

3. In a telephone system, the combination, with a tour party line provided with sub.

nee.

station ringers connected from opposite sides of the line to ground, of a grounded ringing generator, automatic means controlled over said line for connecting either conductor thereof to the ungrounded pole of said generator, and a solenoid interrupter 'cooperating'with said generator to selectively signal all the parties on said party line.

4. In a telephone system, the combination, with a party line provided with substation ringers connected from the same side of the line to ground, of a grounded ringing generator, automatic means including a ringback switch controlled over said line for extending a connection to said generator, automatic means for connecting the ringer side of said line to the ungrounded pole of said generator over a circuit including said extended connection, and code ringing equipment cooperating with said generator to selectively operate said ringers.

5. In a. telephone system, a party line, a plurality of substations thereon, a ringing generator, a solenoid interrupter, and means for causing said generator to apply signalling current to said party line, the said means being controlled by said interrupter according to a predetermined code to selectively signal said substations.

6. In a telephone system, a party line, substation'ringers connected from one side of said line to ground, and ringback apparatus for enabling one-party to call an other on the same line, said apparatus com prising means for transmitting ringing current from a single generator over a circuit including the ringer side of said line according to predetermined codes, automati'c switches whereby one party on said line may establish a connection with said apparatus, and means for projecting current over said circuit and said automatic switches to selebtively signal a station on said party line. I

7. In a telephone system, a party line,! a one bell station and a two bell station on said party line, having ringers connected from the same side of said line to ground, ring back apparatus for enabling either party on said line to call the other, means for extending a connection to said ring back apparatus, and means controlled by said apparatus for projecting signalling current back over said extended connection to selectively signal a station on said line.

8. In a telephone system, a party line, two two bell stations having ringers connected from opposite sides of the line to the ground, ring-back apparatus for enabling either of said stations to signal the other, and automatic means in said ring back apparatus for signalling the calling as Well as the called station.

9. In a telephone system, a party line, two one hell stations on said line having ringers connected from opposite sides of the line to ground, two two bell stations having ringers connected from opposite sides of the line to ground, means including a ring back switch whereby the subscriber at any station on said line can project code ringing currents back over said line from the exchange to signal any other subscriber, and means for ringing the code belonging to the calling station also in case the ringers at the calling and called stations are not connected to the same side of the line.

10. In a telephone system, a party line, two one bell stations on said line having ringers connected from opposite sides of the line to ground, two two bell stations having ringers connected from opposite sides of the line to ground, and code ringing mechanism atthe exchange controlled by any calling subscriber for signalling any other subscriber on the line, said mechanism including means for ringing the code belonging to the calling station also in case the ringers at the calling and called stations are connected to opposite sides of the line but not if the ringers are connected to the same side of the line. i

11. In a telephone system, a party line, stations on said line having ringers connected from opposite sides of the line to ground, ringing equipment including a grounded generator, an automatic switch controlled from said line for extending a connection to said ringing equipment, automatic means controlled by said equipment for variably applying ringing current from said generator to either conductor of said line over said established connection to selectably signal the stations on said party line.

12. In a telephone system, a party line, stations on said line having ringers connected from opposite sides of the line to ground. and code ringing mechanism at the exchange controlled by any calling subscriber for selectively signalling any other subscriber on the line, said mechanism including means for ringing the calling station also in case the ringers at the calling and called stations are connected to opposite sides of the line but not if the ringers are connected to the same side of the line.

Signed by me at Chicago, Cook County, Illinois, this 19th day of October, 1920.

JOHN WICKS. 

